[2] The 9th Mariupol-Khingan was formed from the remnants of the Semenovsky Battalion, a loose formation of locals and Russian volunteers who took part in the fighting in Sloviansk and at Donetsk Airport.

A reformed and strengthened Semenovsky Battalion then took part in the offensive towards Mariupol, and helped to capture the coastal town of Novoazovsk on 28 August 2014.

[3] In February 2016, the former battalion was reformed into the 9th Separate Marine Regiment by a special decree of the head of the self-proclaimed Donetsk People's Republic, Alexander Zakharchenko.

The name of the unit was based on the Soviet 221st Rifle Division which took part in the liberation of Mariupol during World War II.

[5] In January 2023, the regiment was incorporated into the Russian Armed Forces as part of the 1st Donetsk Army Corps and was reformed into the 9th Separate Guards Motor Rifle Brigade.